As related in the copending application, it is often necessary to retrieve a fish from a well during drilling, completion, or workover activities. Many items are equipped with a standard API fishing neck, but this is not always the case. The present invention is an apparatus which retrieves those items which must be hollow, such as tubing. The present invention particularly finds application in retrieval of hollow members. It works with the apparatus in the related disclosure to provide a tool which enables retrieval of practically all types and shapes of fishes.
The present disclosure is to be contrasted with the related application. The present invention utilizes a similar cam and cam follower mechanism. It is able to be latched to on the interior of a fish and released readily. Connection with the fish and release therefrom are easily achieved by repetitive jarring motions which are accomplished without breaking any parts such as shear disks, shear pins, and so on. Engagement and disengagement of the tool with the fish is achieved with a minimum of effort.
The present invention is particularly able to be run on a wireline or can be connected at the bottom of a tubing string to enable fluid flow through the tubing string to wash through the tool to wash away sand or other debris which may block its use. When it is run on a wireline, the wireline can be readily manipulated to provide consecutive jarring motions through the use of mechanical or oil jars which impart the necessary jarring motion to the tool to cause it to engage or disengage. Engagement is achieved when a serrated set of fingers are expanded interiorally of a tubular member and brought into gripping contact with the inner surface, thereby enabling the tool to raise the fish. If the fish is stuck, a subsequent jarring action of the tool causes release and enables the tool to be retrieved. When this occurs, a heavier gauge cable and tool can be subsequently run and exposed to greater stress and strain.